Electric gaseous discharge tube



Sept. 4, 1934. A. CLAUDE 1,972,133

ELECTRIC GASEOUS DISCHARGE TUBE Filed Oct. 22. 1931 Fig.2

Patented Sept. 4, 1934 UNITED STATES PATENT OFFICE Application mm 22,1931,'Serial No. 510,452 In France November 5, 1930 4 Claims. (Cl.I'm-12!) process is obtained a slightly rose tinted white light which bydirect observation appears similar to that of daylight.

For convenience of description white light describes a light which givesthe objects which it illuminates the tint which would be given to themby daylight, that is to say a light which contains radiations throughoutall the regions of the visible spectrum, the said radiations havingintensities which can be compared with those of the solar spectrum.

The object of the present invention is the use of a gaseous atmosphereof the above-mentioned type formed from helium and a small proportion ofneon for forming illuminating devices having however a high energyefficiency For this purpose, according to the present invention adischarge device operating on the arc principle is constructed by usingan atmosphere formed by a mixture of helium and neon in which the neonis in proportion suitable for the production of white light under apressure of gaseous mixture between 3 millimeters and 0,05 millimetersof mercury.

In addition in a device of this kind the cathode can be of one of thetype mentioned in my copending patent application Serial No. 570,451,filed October 22, 1931 for Improvements in electric gaseous dischargedevices..

Further an anode (or anodes in the case of devices having more than oneanode) can be constructed according to one of those described in thesaid patent application and the cathode and an anode (or anodes) can beof the type mentioned above. cathodes and the walls of the dischargedevice can be charged with occluded gas in any desired proportion. theocclusion being able to be extended up to the saturation of the saidelements according to the said patent application.

By the combined utilization of these various means it is possible toprovide an installation operating by are with an electric dischargeapparatus containing a mixture of helium and neon and at the same timepresenting a series of tech- The anode (or anodes) the nical advantagesof capital importance which have not been obtained up to date. Amongthese advantages can be mentioned, firstly the high luminouspower o! thedischarge apparatus, secondly the quality of the light obtained, thirdlythe high energetic efliciency of the installation and fourthly the longlife of the functioning of the discharge apparatus without anyappreciable change in the preceding advantages.

It is to be noted that these results are absolutely new by reason on onehand of the extreme facility with which the rare gases are absorbed inthe discharge devices at present used and on the other hand of the lowpressure of the mixture of rare gases used here, which conditionincidentally would normally exaggerate the said damaging effect, andthey are new also by reason of the rather small proportion of neonexisting in the above-mentioned mixture of rare gases. This proportionis such that the volume of neon contained in a discharge tube of usualdimension is several thousandths of a cubic centimeter and at atmospherepressure.

The discharge apparatus according to the present invention also havevarious other properties which are as interesting from the point of viewof their construction as from their operation; amongst these can becited the following:

Firstly in opposition to arc operated tubes charged with pure neon theminimum specific consumption in the positive column exclusive of theloss of energy at the electrodes of a discharge apparatus according tothe present invention is independent of the diameter of this column butlike the pure neon tubes it is obtained with a pressure which is thelower, the greater the diameter of the tube and this pressure isapproximately in the inverse ratio of the diameter for example it is 0,2millimeters for a tube of millimeters and it is 0,55 millimeters for atube of 20 millimeters.

Secondly in opposition to are operated neon tubes in the tubes madeaccording to the present invention irrespective of diameter, the minimumvoltage necessary for the feed for any given value of pressure coincidesalmost exactly with the minimum specific consumption in such a way thatthe tube, the luminous efliciency of which is the highest, is also thatwhich for a given length functions .under the lowest voltage or whichcan be the longest for a given feed voltage.

The invention is more particularly described with reference to thedrawing in which:-

Figure 1 shows curves indicating for various diameters of the tube thevariation of the specific consumption under given pressure values, thecurrent intensity being constant.

Figure 2 shows curves indicating for various diameters of tubes the teedvoltage under given preszure values, the current intensity being constanThese curves are taken out of a double system of curves obtainedexperimentally by'the applicant, each curve corresponding to apredetermined diameter of the tube.

In Figure 1, the pressures have been marked on the line of the abscissain millimeters 0t mercury tor the mixture of helium and neon used andthe specific consumptions oi the luminous column have been marked on theordinates, these consumptions being shown in watts per candle. Eachcurve of this figure gives the variation o! the specific consumption fora tube of predetermined diameter under the effect of the variation ofpressure prevalent in this tube. This curve shows that there is aminimum of specific consumption. The series of curves 0! this figureshow in addition that this minimum has practically the same value forall diameters of tube.

The table below gives the diameters of various tubes which have beenused for forming curves oi Fig. 1'.

Diameter Curves womb.

warm. I 06 II so in so abscissa line in millimeters of mercury and thegradient oi potential in the positive column is expressed along theordinates in volts per meter of the positive column the intensitiesbeing 01 the order of several amperes.

The table given below shows the diameters of the various helium neontubes which have been used for forming these curves.

Diameter of the tube Miuimam These curves show that for each diameter ofthe tube there is a pressure of the mixture of helium and neon for whichthe tube definitely functions with a minimum voltage.

In addition when comparing the corresponding curves of Figs. 1 and 2 itis shown that there is minimum voltage and minimum specific consumptionfor a predetermined diameter at substantially the same pressure so thata discharge apparatus established according to the present inventionwith a given mixture 01 helium and the at pee IntIIity i a; i it-E mmm.

2 amp. 20mm.

Theinfiuenceotthepresmreusedisparticularly important. The above data wasobtained from experiments in which white light was produced.

The values stated above are shown by way of example, it being understoodthat the ambit of the present invention is not exceeded by usingdifierent diameters and intensities in combination with pressuresincluded in the above limits.

It is an important fact when the composition of the mixture or heliumand neon varies between the limits stated above, the specificconsumption and the feed voltage do not appreciabLv change. I 4

In the present application, it is to be understood that the expressionelectric gaseous discharge tube" means not only an electric gaseousdischargetubethatistosayanapparatuswithm an elongated cylindricalchamber, but also anyapparatus of the kind described provided with achamber oi. any other shape.

atmospherebeingatapressure 'e sinsbetweenliilv 3 millimeters and 0,05millimeters of mercury, the anode of the discharge apparatus having ananodic zone, the surface of which has a minimum value determined by thepressure of the gaseous mass in the discharge apparatus, this valueranging between 1 square centimeter per ampere when this pressure is 3millimeters of mercury and 8 square centimeters per ampere when thepressure is 0,05 millimeters.

2. An electric gaseous discharge illuminating apparatus adapted tooperate on the arc principle, comprising an envelope containing anatmosphere consisting of a mixture of helium and neon in which the neonis in such proportion as to obtain a white light under the action of anelectric discharge in the said atmosphere, said atmosphere being at apressure ranging between 3 millimeters and 0,05 millimeters of mercury,the anode of the discharge apparatus having an anodic zone, the area ofwhich at the minimum is one-seventh the total area of the anode.

3. An electric gaseous discharge illuminating apparatus adapted tooperate on the arc principle, comprising an envelope containing anatmosphere consisting of a mixture of helium and neon in which the neonis in such proportion as to obtain a white light under the action of anI electric discharge in the said atmosphere, said atmosphere being at apressure ranging between 3 millimeters and 0,05 millimeters of mercury,the anode of the discharge apparatus being hollow, the depth of thehollow in the electric field being at least equal to the diameter ofsaid anode.

4. An electric gaseous discharge illuminating apparatus adapted tooperate on the arc principle, comprising an envelope containing anatmosphere consisting of a mixture of helium and neon in which the neonis in such proportion as to obtain a white light under the action of anelectric discharge in the said atmosphere, said atmosphere being at apressure ranging between 3 millimeters and 0,05 millimeters of mercury,the anode of the discharge apparatus being provided with a di-electriclining or covering on the parts of said anode which are apt to becomedisintegrated.

ANDRE CLAUDE.

